Here are some of the poses I had a pair of Sebastian and Ciel cosplayers do at a local con (both were guys so I was trying to make it not super uncomfortable for them despite them asking for the photos xD)

Sebastian standing behind you with one hand over your cursed eyed
Sebastian kneeling while doing his hand over chest pose with you looking down at him or extending your hand to him
You and Sebastian holding your cane up with your hands close to eachother
If you are sitting in the chair, Sebastian leaning over the back of the chair as if he was going to whisper something to you